Real Estate Appraisal Methods: Sales Comparison, Cost & Income Approaches

Appraisal questions appear on virtually every real estate licensing exam. You need to know the three fundamental approaches to value, when each is used, how to perform the basic calculations, and the key terminology that surrounds the appraisal process. This guide breaks down each approach with clear formulas and worked examples.

The Three Approaches to Value: An Overview

Professional appraisers use three distinct methods to estimate a property's market value. Each approach is suited to different property types and situations, and a competent appraiser typically uses at least two approaches and reconciles the results into a final opinion of value.

• Sales Comparison Approach: Best for single-family homes and residential properties where there are plenty of recent comparable sales. This is the most intuitive and widely used approach.
• Cost Approach: Best for unique or special-purpose properties (schools, churches, government buildings) and new construction where comparable sales are scarce. Also used as a check on the other approaches.
• Income Capitalization Approach: Best for income-producing properties (apartment buildings, office buildings, shopping centers, industrial properties). Value is derived from the property's ability to generate income.

The Sales Comparison Approach

The sales comparison approach estimates value by comparing the subject property to recently sold similar properties (called "comparables" or "comps"), then adjusting for differences. The underlying principle is substitution: a rational buyer won't pay more for a property than the cost of acquiring an equally desirable substitute.

How It Works

1. Identify 3–5 recently sold properties that are similar to the subject in location, size, age, condition, and features.
2. Adjust the sale price of each comparable to account for differences from the subject property. If the comparable has a feature the subject lacks (e.g., a swimming pool), subtract the value of that feature from the comparable's price. If the subject has a feature the comparable lacks, add that value.
3. The adjusted prices of the comparables provide a range. The appraiser reconciles them into a single value estimate, giving more weight to the comparables requiring the fewest adjustments.

Example

Subject property: 3-bedroom, 2-bath, 1,800 sq ft, no pool, 2-car garage.

Comparable A sold for $320,000: 3-bed, 2-bath, 1,850 sq ft, pool, 2-car garage. Adjustments: +$5,000 for subject's smaller size (comparable is larger, so it's worth more — subtract from comparable, which means add to subject's implied value), -$15,000 for pool (subject lacks pool, so comparable's price must be reduced). Adjusted value: $320,000 + $5,000 - $15,000 = $310,000.

Comparable B sold for $305,000: 3-bed, 2-bath, 1,750 sq ft, no pool, 1-car garage. Adjustments: -$3,000 for smaller size, +$8,000 for extra garage bay. Adjusted value: $305,000 - $3,000 + $8,000 = $310,000.

Reconciled value estimate: approximately $310,000.

The Cost Approach

The cost approach is based on the principle of substitution as well: a buyer won't pay more for an existing property than the cost to build an equivalent new one. The formula is:

Value = Replacement Cost New − Depreciation + Land Value

Step 1: Estimate Replacement Cost New

This is what it would cost to build an identical structure at current prices, using modern materials and methods. Appraisers use three methods: the square-foot method (cost per square foot × total square footage), the unit-in-place method (cost of each component — foundation, framing, roofing, etc.), and the quantity survey method (detailed material and labor estimates — most accurate but rarely used for residential).

Step 2: Subtract Depreciation

Depreciation is loss in value from any cause. The exam tests three types:

• Physical Deterioration: Wear and tear from age, use, and the elements. Can be curable (peeling paint, worn carpet) or incurable (foundation settling).
• Functional Obsolescence: Loss in value due to outdated design or layout. A four-bedroom house with only one bathroom has functional obsolescence. Can be curable (adding a bathroom is economically feasible) or incurable.
• Economic (External) Obsolescence: Loss in value due to factors outside the property — a new highway next door, a declining neighborhood, a closed factory. Always incurable because the property owner can't control external conditions.

Step 3: Add Land Value

Land is valued separately, typically using the sales comparison approach (comparing to recent vacant land sales), since land doesn't depreciate.

Example

A 10-year-old house has a replacement cost new of $250,000. Physical deterioration is estimated at $30,000, functional obsolescence at $10,000, and economic obsolescence at $5,000. The land is worth $60,000. Value = $250,000 − $45,000 + $60,000 = $265,000.

The Income Capitalization Approach

For income-producing properties, value is a function of the income the property generates. The fundamental formula is:

Value = Net Operating Income (NOI) ÷ Capitalization Rate (Cap Rate)

Calculating Net Operating Income (NOI)

NOI is the property's annual income after operating expenses but before debt service (mortgage payments) and income taxes:

Gross Scheduled Rent − Vacancy & Collection Loss = Effective Gross Income
Effective Gross Income + Other Income − Operating Expenses = NOI

Operating expenses include property taxes, insurance, maintenance, utilities, management fees, and reserves for replacement. They do not include mortgage payments, depreciation, or capital improvements.

Capitalization Rate

The cap rate is the rate of return an investor expects on the property. It's derived from market data — what similar properties are selling for relative to their NOI. A higher cap rate implies higher risk (and a lower value for a given NOI). A lower cap rate implies lower risk and higher value.

Example

An apartment building generates $120,000 in gross scheduled rent. Vacancy and collection losses are 5% ($6,000). Effective gross income is $114,000. Operating expenses are $45,000. NOI = $114,000 − $45,000 = $69,000. Market cap rate for similar properties is 8% (0.08). Value = $69,000 ÷ 0.08 = $862,500.

Gross Rent Multiplier (GRM)

The GRM is a quick, rough valuation tool — not a full appraisal approach, but it appears on the exam. The formula:

GRM = Sale Price ÷ Gross Monthly Rent

If similar properties in the area sell for about 120 times their monthly rent, and the subject property rents for $2,000/month, its estimated value is $2,000 × 120 = $240,000. The GRM is useful for quick comparisons but ignores expenses, vacancy, and differences between properties.

Key Appraisal Principles for the Exam

• Highest and Best Use: The legally permissible, physically possible, financially feasible, and maximally productive use of a property. This analysis drives which appraisal approach is most appropriate.
• Conformity: A property achieves maximum value when it conforms to its surroundings — a modest house in a neighborhood of mansions is worth less than the same house in a neighborhood of similar homes.
• Progression and Regression: A lower-value property surrounded by higher-value properties tends to increase in value (progression). A higher-value property surrounded by lower-value properties tends to decrease in value (regression).
• Plottage Value: The increase in value created by assembling adjacent parcels into a single larger tract. Two $50,000 lots combined might be worth $130,000 because the larger parcel enables a more valuable use.
• Anticipation: Value is created by the expectation of future benefits. An apartment building's value today depends on the income it's expected to generate tomorrow.